Fabricated trusses of the type assembled on the present machine are disclosed in U.S. Pat. No. 4,078,352 and prior apparatus for assembling such trusses is disclosed in U.S. Pat. No. 4,002,116. The trusses comprise upper and lower wood chords which may be two by four or other rectangular shapes having end and intermediate wood spacers forming a preliminary truss frame. Metal V-webs, formed as sheet metal stampings having end and apex plates with vertical teeth struck therein and reinforcing ribs formed in the intermediate V-legs are pressed in opposed relation on either side of a pair of spaced wooden chords to form an elongated fabricated joist. The wood chords may be assembled in either flat or on edge relationship to each other utilizing the same V-web toothed metal plate connectors and in practice various chord sizes such as two by three, two by four, two by five and two by six have been employed with V-web connector heights such as 8", 91/4", 103/4" and 16".
The prior mechanical apparatus employed for assembling such fabricated truss joists comprised a pair of parallel rails upon which brackets were attached for supporting the chords above and along side each of the rails so that web connectors could first be laid upon the rails with teeth upwardly extending for embedding into the downward faces of the chords and upper webs could be aligned by laying them over the top faces of the chords to form a truss having aligned webs on opposite faces of the chords. A pair of clamping devices were movable along the rails for selectively clamping aligned pairs of connector portions on opposite chords against the wood embedding the teeth therein. Sequential movement of the clamping devices to pairs of connectors and clamping thereof involved intermittent step movement and clamping along the length of the joist limiting the speed of assembly to 2,000 linear feet per day with a three man crew compared with speeds in the order of ten times as great on the apparatus disclosed herein.